The Phase I SBIR has successfully identified new zinc, electrolyte, and separator combinations for sealed nickel-zinc batteries which will permit extended operation for left ventricular assist devices (LVAD). Based on these results, the Phase II SBIR outlines a continued program which will result in the development of a sealed 4.7 Ah/12 volt Ni-Zn battery which has gravimetric energy density of 88 Wh/kg (40 Wh/lb) and a volumetric energy density of 120 Wh/l (2.0 Wh/in3). The specific weight of the battery will be about 0.64 kg (1.4 lbs). The unit will be capable of powering an LVAD for eight hours before recharging. The proposed program will center on continued research work to extend the cycle life to beyond 500 cycles. Hardware development will focus on a sealed battery and plastic roll- bonded electrodes technology which yields lightweight components with high electrochemical utilization. The improved cell chemistries will be engineered into prototype batteries in a monobloc construction which can be worn as a beltpack. PROPOSED COMMERCIAL APPLICATION: The small batteries will have eventual application in the medical field for LVADs, artificial hearts, portable insulin pumps, etc. and in a wider commercial application for lap-top computers, and portable communication equipment. Larger Ni-Zn batteries may find use in electric vehicles.